MAKE(1)                                                  User Commands                                                 MAKE(1)

NAME
       make - GNU make utility to maintain groups of programs

SYNOPSIS
       make [OPTION]... [TARGET]...

DESCRIPTION
       The make utility will determine automatically which pieces of a large program need to be recompiled, and issue the com‐
       mands to recompile them.  The manual describes the GNU implementation of make, which was written  by  Richard  Stallman
       and  Roland McGrath, and is currently maintained by Paul Smith.  Our examples show C programs, since they are very com‐
       mon, but you can use make with any programming language whose compiler can be run with a shell command.  In fact,  make
       is  not  limited  to programs.  You can use it to describe any task where some files must be updated automatically from
       others whenever the others change.

       To prepare to use make, you must write a file called the makefile that describes the relationships among files in  your
       program,  and  the  states the commands for updating each file.  In a program, typically the executable file is updated
       from object files, which are in turn made by compiling source files.

       Once a suitable makefile exists, each time you change some source files, this simple shell command:

              make

       suffices to perform all necessary recompilations.  The make program uses the makefile description and the  last-modifi‐
       cation times of the files to decide which of the files need to be updated.  For each of those files, it issues the com‐
       mands recorded in the makefile.

       make executes commands in the makefile to update one or more target names, where name is typically a program.  If no -f
       option is present, make will look for the makefiles GNUmakefile, makefile, and Makefile, in that order.

       Normally  you  should call your makefile either makefile or Makefile.  (We recommend Makefile because it appears promi‐
       nently near the beginning of a directory listing, right near other important files such as  README.)   The  first  name
       checked,  GNUmakefile,  is not recommended for most makefiles.  You should use this name if you have a makefile that is
       specific to GNU make, and will not be understood by other versions of make.  If makefile is '-', the standard input  is
       read.

       make  updates  a target if it depends on prerequisite files that have been modified since the target was last modified,
       or if the target does not exist.

OPTIONS
       -b, -m
            These options are ignored for compatibility with other versions of make.

       -B, --always-make
            Unconditionally make all targets.

       -C dir, --directory=dir
            Change to directory dir before reading the makefiles or doing anything else.  If multiple -C  options  are  speci‐
            fied,  each  is interpreted relative to the previous one: -C / -C etc is equivalent to -C /etc.  This is typically
            used with recursive invocations of make.

       -d   Print debugging information in addition to normal processing.  The debugging information says which files are  be‐
            ing  considered for remaking, which file-times are being compared and with what results, which files actually need
            to be remade, which implicit rules are considered and which are applied---everything interesting  about  how  make
            decides what to do.

       --debug[=FLAGS]
            Print  debugging information in addition to normal processing.  If the FLAGS are omitted, then the behavior is the
            same as if -d was specified.  FLAGS may be a for all debugging output (same as using -d), b for basic debugging, v
            for more verbose basic debugging, i for showing implicit rules, j for details on invocation of commands, and m for
            debugging while remaking makefiles.  Use n to disable all previous debugging flags.

       -e, --environment-overrides
            Give variables taken from the environment precedence over variables from makefiles.

       -E string, --eval string
            Interpret string using the eval function, before parsing any makefiles.

       -f file, --file=file, --makefile=FILE
            Use file as a makefile.

       -i, --ignore-errors
            Ignore all errors in commands executed to remake files.

       -I dir, --include-dir=dir
            Specifies a directory dir to search for included makefiles.  If several -I options are used to specify several di‐
            rectories,  the directories are searched in the order specified.  Unlike the arguments to other flags of make, di‐
            rectories given with -I flags may come directly after the flag: -Idir is allowed, as well as -I dir.  This  syntax
            is allowed for compatibility with the C preprocessor's -I flag.

       -j [jobs], --jobs[=jobs]
            Specifies  the number of jobs (commands) to run simultaneously.  If there is more than one -j option, the last one
            is effective.  If the -j option is given without an argument, make will not limit the number of jobs that can  run
            simultaneously.

       -k, --keep-going
            Continue as much as possible after an error.  While the target that failed, and those that depend on it, cannot be
            remade, the other dependencies of these targets can be processed all the same.

       -l [load], --load-average[=load]
            Specifies that no new jobs (commands) should be started if there are others jobs running and the load  average  is
            at least load (a floating-point number).  With no argument, removes a previous load limit.

       -L, --check-symlink-times
            Use the latest mtime between symlinks and target.

       -n, --just-print, --dry-run, --recon
            Print the commands that would be executed, but do not execute them (except in certain circumstances).

       -o file, --old-file=file, --assume-old=file
            Do  not  remake  the file file even if it is older than its dependencies, and do not remake anything on account of
            changes in file.  Essentially the file is treated as very old and its rules are ignored.

       -O[type], --output-sync[=type]
            When running multiple jobs in parallel with -j, ensure the output of each job is collected  together  rather  than
            interspersed with output from other jobs.  If type is not specified or is target the output from the entire recipe
            for each target is grouped together.  If type is line the output from each command line within a recipe is grouped
            together.   If  type  is recurse output from an entire recursive make is grouped together.  If type is none output
            synchronization is disabled.

       -p, --print-data-base
            Print the data base (rules and variable values) that results from reading the makefiles; then execute as usual  or
            as  otherwise  specified.   This also prints the version information given by the -v switch (see below).  To print
            the data base without trying to remake any files, use make -p -f/dev/null.

       -q, --question
            ``Question mode''.  Do not run any commands, or print anything; just return an exit status that  is  zero  if  the
            specified targets are already up to date, nonzero otherwise.

       -r, --no-builtin-rules
            Eliminate use of the built-in implicit rules.  Also clear out the default list of suffixes for suffix rules.

       -R, --no-builtin-variables
            Don't define any built-in variables.

       -s, --silent, --quiet
            Silent operation; do not print the commands as they are executed.

       --no-silent
            Cancel the effect of the -s option.

       -S, --no-keep-going, --stop
            Cancel the effect of the -k option.

       -t, --touch
            Touch  files  (mark them up to date without really changing them) instead of running their commands.  This is used
            to pretend that the commands were done, in order to fool future invocations of make.

       --trace
            Information about the disposition of each target is printed (why the target is being rebuilt and what commands are
            run to rebuild it).

       -v, --version
            Print the version of the make program plus a copyright, a list of authors and a notice that there is no warranty.

       -w, --print-directory
            Print a message containing the working directory before and after other processing.  This may be useful for track‐
            ing down errors from complicated nests of recursive make commands.

       --no-print-directory
            Turn off -w, even if it was turned on implicitly.

       -W file, --what-if=file, --new-file=file, --assume-new=file
            Pretend that the target file has just been modified.  When used with the -n flag, this shows you what would happen
            if  you  were to modify that file.  Without -n, it is almost the same as running a touch command on the given file
            before running make, except that the modification time is changed only in the imagination of make.

       --warn-undefined-variables
            Warn when an undefined variable is referenced.

EXIT STATUS
       GNU make exits with a status of zero if all makefiles were successfully parsed and no targets that were  built  failed.
       A status of one will be returned if the -q flag was used and make determines that a target needs to be rebuilt.  A sta‐
       tus of two will be returned if any errors were encountered.

SEE ALSO
       The full documentation for make is maintained as a Texinfo manual.  If the info and  make  programs  are  properly  in‐
       stalled at your site, the command

              info make

       should give you access to the complete manual.

BUGS
       See the chapter ``Problems and Bugs'' in The GNU Make Manual.

AUTHOR
       This  manual  page  contributed by Dennis Morse of Stanford University.  Further updates contributed by Mike Frysinger.
       It has been reworked by Roland McGrath.  Maintained by Paul Smith.

COPYRIGHT
       Copyright © 1992-1993, 1996-2020 Free Software Foundation, Inc.  This file is part of GNU make.

       GNU Make is free software; you can redistribute it and/or modify it under the terms of the GNU General  Public  License
       as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

       GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
       of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

       You should have  received  a  copy  of  the  GNU  General  Public  License  along  with  this  program.   If  not,  see
       http://www.gnu.org/licenses/.

GNU                                                    28 February 2016                                                MAKE(1)
